Antiviral agents

ABSTRACT

This invention relates to compounds, compositions, uses and methods for inhibiting viral and retroviral replication and for treating viral and retroviral infections via the administration of various compounds, including antioxidants, preferably compounds corresponding to the formula ##STR1## wherein n=1, 2, 3, or 4; m=0 or 1; X is O, S or CH 2  ; R 1  is hydrogen or tertiary butyl or lower alkyl of from one to six carbon atoms, inclusive; R 2  is tertiary butyl or lower alkyl of from one to six carbon atoms, inclusive; and R 3  is hydrogen or alkyl or aryl or mixed alkyl/aryl, containing a total of 5-25 carbon atoms.

This application is a continuation of U.S. patent application Ser. No.08/130,168, filed Sep. 30, 1993, allowed, which is a continuation ofSer. No. 07/550,528, filed Jul. 10, 1990, abandoned, which is a CIP ofSer. No. 07/452,737 filed Dec. 19, 1989 abandoned, which is a CIP ofSer. No. 07/381,132, filed Jul. 14, 1989 issued as U.S. Pat. No.4,985,465, Jan. 15, 1991, all of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

Diseases associated with viral and retroviral infections are majormedical, veterinary and agricultural problems in the United States andworldwide. Diseases of known viral origin include chicken pox, thecommon cold, cytomegalovirus disease (CMV), dengue fever, encephalitis,hoof-and-mouth disease, herpes infections, influenza,keratoconjunctivitis, measles, mumps, Newcastle disease, poliomyelitis,rabies, rubella, scrapie, shingles, smallpox, tick fever, West NileFever, and yellow fever, to name but a few. An especially seriousproblem at the present time is the rapid escalation in reported cases ofAIDS (Acquired Immune Deficiency Syndrome), whose causative agent isstrongly suspected to be HIV (Human Immunodeficiency Virus).

There are urgent and compelling reasons for the development of moreefficacious and safer treatments of viral and retroviral infections. Itis estimated that at least one and a half million people in the UnitedStates alone have been infected with the human immunodeficiency (HIV) orAIDS virus. HIV causes a decay of a major arm of the immune system, theimmune helper cells (T4 helper or CD4⁺ helper cells). This decay leadsto a wide spectrum of diseases, generally called HIV disease, of whichAIDS is the most serious and devastating form. It is anticipated thatover one third of the budget for medical care in the U.S. will beconsumed on HIV disease. There is an escalating incidence of other viraldiseases as well. For example, cytomegalovirus (CMV) infection israpidly increasing in the teenage population of the United States.

We have noted that two commonly-used antioxidants and preservatives,butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) havebeen reported to have some efficacy in ameliorating some viralinfections. Some of these reports are summarized below:

    ______________________________________                                        VIRUS           REFERENCE                                                     ______________________________________                                        Newcastle Disease                                                                             Brugh, M., "Chemical Regulation                                 Virus of Immunity", in Veterinary Med.,                                        A. R. Liss, 1984, pp. 229-234;                                                Brugh, M., Science 197: 1291                                                  (1977); Winston, et al., Am. J.                                               Vet. Res. 41: 391 (1980).                                                    HIV Reimund, E., Medical (HIV)                                                 Hypotheses 23: 39 (1987); Aloia,                                              et al., PNAS 85: 900 (1988).                                                 Bacteriophage PM2 Cupp, J., et al., Antimicrobial                              Agents and Chemotherapy 8: 698                                                (1975).                                                                      Pseudorabies Virus Pirtle, E. C., et al., Am. J. Vet.                         (PRV) Res. 47: 1892 (1986).                                                   Bacteriophage (φ6) Wanda, P., et al., Antimicrobial                        Agents and Chemotherapy 10: 96                                                (1976).                                                                      Herpes Simplex Virus Keith, A. D., et al., Proc. Soc.                         (HSV-1) Exptl. Biol. & Med. 170: 237                                           (1982).                                                                      Herpes Simplex Freeman, D. J., et al., Clin.                                  Labialis (HSL) Pharmacol. Ther. 38: 56 (1985).                                Semliki Forest Virus Kim, K. S., et al., J. Infec.                            (SFV) Dis. 138: 91 (1985).                                                    Cytomegalovirus (CMV) Kim, K. S., et al., J. Infec.                            Dis. 138: 91 (1985).                                                       ______________________________________                                    

It has been observed that certain viruses and retroviruses including,for example, cytomegalovirus (CMV), herpes simplex virus, herpes zostervirus, Epstein-Barr virus (EBV), Newcastle Disease virus, Semliki Forestvirus, influenza viruses, pseudorabies virus, and human immunodeficiencyvirus (HIV), are of the lipid membrane variety. Further, we havehypothesized that BHT, BHA, and/or the compounds of the presentinvention may have some impact upon said membranes, albeit othermechanisms not presently known may be responsible for the unanticipatedefficacy of the compounds of the present invention.

In addition, it has been theorized that free oxygen radicals may beinvolved in the pathogenesis of certain viral infections (see Oda, etal., Science 244: 974-976 (1989), and that antioxidants may have animpact upon viral or retroviral infections (see Hendler, S., "The OxygenBreakthrough," William Morrow and Company, Inc., New York, 1989; orHendler, S., "The Complete Guide to Anti-Aging Nutrients," Simon andSchuster, New York, 1984.)

As a result of our independent observations, we believe there might besubstances possessing the ability to fluidize viral membranes, orotherwise affect their structures, in ways that make them less capableof infecting cells. It is to be expressly understood that the inventiondisclosed herein is not limited to or by a particular theory ofoperation, however.

In recent years, many investigators have proposed novel treatments forcombating insidious forms of disease, many involving viruses orretroviruses as the causative agents. Due to the many differences thatseparate these pathogens--including, for example, their structure, theirmethod of replication and their susceptibility to or resistance tovarious treatment modalities--one might not expect a single method ofinhibiting the development of viral and retroviral infections o befeasible. Nevertheless, such a methodology is now available, due to theunanticipated efficacy of known and novel compounds in affectingmembrane fluidity, among other things.

Therefore, in response to this pervasive need for safer and moreefficacious treatments of viral and retroviral infections, and in lightof our observations, we undertook to design and synthesize a variety ofnew molecules and to propose methods for their use, in order to furtherexplore the relationship of structure and activity, in the hope ofdiscovering even more highly effective antiviral substances.

The present invention also relates to methods for inhibiting viral andretroviral infections via use of known compounds with unexpectedefficacy in combating viral and retroviral infections. The presentinvention also suggests the use of novel compounds to inhibit theseinfections, as well as methods for their use in living organisms.

SUMMARY OF THE INVENTION

Ideally, one type of substance that could conceivably affect theinfectivity of a viral or retroviral agent should have some or all ofthe following characteristics: a) solubility in lipid membranes, withpreferential solubility in the lipid membranes of viruses as opposed tothe cells of the body of the host; b) ability to extract cholesterolfrom viral membranes; c) antioxidant ability to prevent lipidperoxidation; d) easy absorbability into the body; e) the ability topenetrate the blood-brain barrier; and f) a very hightherapeutic-to-toxicity index. It is anticipated that all membranedviruses, including herpes simplex, herpes zoster, CMV, EBV, influenzaviruses, and the human immunodeficiency viruses may be inhibited to someextent by such substances at doses that will not produce toxic sideeffects. In addition, it is also anticipated that the within inventionmay be successfully applied to viruses and retrovirus which lackenvelopes, including the DNA and RNA viruses. The invention disclosedwithin is not limited to or by a particular theory of operation,however. It is simply suggested that the observed efficacy ofcompositions suggested by the present disclosure may be due, at least inpart, to the characteristics noted above.

This invention relates to novel compositions and methods for using samefor inhibiting viral and retroviral infections. In particular, the useof sterically hindered phenolic antioxidants is suggested. Even moreparticularly, the invention is directed to methods for using novelpharmaceutical compositions to inhibit viral and retroviral infectionsin vivo wherein the compositions comprise an effective amount of abis(dialkylphenol) mercaptal or a bis(dialkylphenol) mercaptolecompound.

One candidate substance which proved to have unexpectedly promisingantiviral activity in this regard is the drug probucol, which isobtainable under the name Lorelco (Merrell Dow Pharmaceuticals, Inc.).Methods for utilizing this particular compound in lowering serumcholesterol are set forth in U.S. Pat. No. 3,862,332, which isincorporated herein by reference.

Therefore, one embodiment of the present invention discloses a methodfor inhibiting viral and retroviral infections or for inhibiting viraland retroviral replication in living organisms comprising administeringto living organisms an effective amount of a compound, or a compositioncontaining a compound, corresponding to the formula ##STR2## whereinn=1, 2, 3, or 4; wherein m=0 or 1; wherein X represents O, S or CH₂ ;wherein R₁ represents hydrogen or tertiary butyl or lower alkyl of fromone to six carbon atoms, inclusive; wherein R₂ represents tertiary butylor lower alkyl of from one to six carbon atoms, inclusive; and whereinR₃ represents hydrogen or alkyl or aryl or mixed alkyl/aryl, containinga total of 5-25 carbon atoms. In a preferred embodiment, R₁ and R₂represent tertiary butyl.

The present embodiment additionally discloses a method for inhibitingviral and retroviral infections in living organisms comprisingadministering to a living organism an effective amount of an antioxidantcompound. In one embodiment of the present invention, the antioxidantcompound may also be sterically hindered; in another preferredembodiment, the compound is also phenolic.

In one preferred embodiment, the compounds disclosed herein areincorporated in a pharmaceutically acceptable carrier or excipient.Preferred methods of administering the compounds of the presentinvention include parenteral, oral, intraperitoneal, transdermal andtopical administration, as well as administration via inhalation.

It is thus one object of this invention to provide methods for usingnovel compounds or pharmaceutical compositions to inhibit viral andretroviral infections, by administering them to living organisms,including plants and animals. A further object of this invention is toprovide a novel method for treating viral and retroviral infections inliving organisms. Another object of the present invention is to providea novel method for inhibiting viral and retroviral replication in livingorganisms. Yet another object of the invention is to provide novel usesfor compositions which have the ability to inhibit viral and retroviralreplication in living organisms, and which have low toxicity at dosagelevels consistent with their indicated activity. A further object ofthis invention is to suggest methods for the alleviation of viral andretroviral infections in a variety of organisms, including plants,animals, and more particularly, in mammals, including humans.

The present invention also discloses methods for treating viral andretroviral infections or for inhibiting viral and retroviral replicationin living organisms comprising administering to living organisms aneffective antiviral amount of the aforementioned compounds.

In one embodiment of the present invention, the compound used accordingto the disclosed method has antioxidant properties; in anotherembodiment, it may also be phenolic; in yet another embodiment, thecompound may be a sterically hindered phenol.

Another aspect of the invention is a composition useful in the treatmentof viral and retroviral infections or for inhibiting viral andretroviral replication in living organisms comprising an effectiveantiviral amount of a compound corresponding to the formula ##STR3##wherein n=1, 2, 3, or 4, wherein m=0 or 1, wherein X represents O, S orCH₂, wherein R₁ represents hydrogen or tertiary butyl or lower alkyl offrom one to six carbon atoms, inclusive, R₂ represents tertiary butyl orlower alkyl of from one to six carbon atoms, inclusive, and wherein R₃represents hydrogen or alkyl or aryl or mixed alkyl/aryl, containing atotal of 5-25 carbon atoms. In a preferred embodiment, R₁ and R₂represent tertiary butyl.

Examples of compounds that may be utilized according to the disclosedembodiments include bis(3,5-di-tert-butyl-4-hydroxyphenyl) acetonemercaptole, bis(3,5-di-tert-butyl-4-hydroxyphenyl) butanone mercaptole;bis(3-tert-butyl-4-hydroxy-5-isopropylphenyl) acetone mercaptole;bis(3-tert-butyl-4-hydroxy-5-methylphenyl) acetone mercaptole;1,12-di(3,5-di-tert-butyl-4-hydroxyphenylthio)dodecane;α,α'-di(3,5-di-tert-butyl-4-hydroxyphenylthio)-p-xylene;1,4-di(3,5-di-tert-butyl-4-hydroxyphenlythio)butane; acetonebis(3,5-di-tert-butyl-4-hydroxyphenyl) mercaptole ("probucol"); bis(3,5-di-tert-butyl-4-hydroxyphenyl) sulfide; dimethyl gamma-ketopimelatebis(3,5-di-tert-butyl-4-hydroxyphenyl) mercaptole;2,6-di-tert-butyl-4-methylphenol (BHT);4,4'-thiobis(6-tert-butyl-o-cresol),1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl) benzene;and 4,4'-methylenebis(2,6-di-tert-butylphenol).

Other examples include 3,5-di-t-butyl-4-hydroxyphenylβ-D-thioglucopyranoside; bis(3,5-di-t-butyl-4-methoxyphenyl) mercaptole;2,6-di-t-butyl-4-(dodecylthio)phenol; 2,6-di-t-butyl-4-(octadecylthio)phenol; 1,10-di(3,5-di-t-butyl-4-hydroxyphenylthio)decane;1,14-di(3,5-di-t-butyl-4-hydroxyphenylthio)tetradecane; 2-octanonebis(3,5-di-t-butyl-4-hydroxyphenyl)mercaptole; acetoacetic acidbis(3,5-di-t-butyl-4-hydroxyphenyl) mercaptole; 2,6-di-tert-butyl--dimethylamino-p-cresol;1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-benzene("Ethanox.sub.| 330"); octadecyl3,5-di-tert-butyl-4-hydroxyhydrocinnamate ("Ethanox.sub.| 376");6-tert-butyl-2,4-dimethylphenol ("Ralox.sub.| 624"); tetrakis[methylene(3,5-di-tert-butyl-4-hydroxyhydrocinnamate)] methane ("Ralox₅₁630"); 2,2'-methylene-bis(4-methyl-6-tert-butylphenol) ("Ralox.sub.|2246"); tert-butylhydroquinone ("Tenox.sub.| TBHQ");2,6-dicyclohexyl-p-cresol (Ethyl Corporation, Baton Rouge, La.);bis(3,5-di-tert-butyl-4-hydroxyphenyl) methane ("Ethanox.sub.| 702");and methylene bridged polyalkyl phenols, comprising4,4'-methylenebis(2,6-di-tert-butylphenol), solvents, and alkylatedphenols, principally 2,4,6 tri-tert-butylphenol ("Ethanox.sub.| 728").(Ethanox.sub.| is a registered trademark of Ethyl Corporation;Ralox.sub.| is a registered trademark of Raschig AG, Ludwigshafen,Germany; and Tenox.sub.| is a registered trademark of Eastman ChemicalProducts, Kingsport, Tenn.)

In one preferred embodiment, the compounds disclosed herein areincorporated in a pharmaceutically acceptable carrier or excipient.Preferred methods of administering the compounds of the presentinvention include parenteral, oral, intraperitoneal, transdermal,topical, and liposomal administration, as well as administration viainhalation.

In particular preferred embodiments of the composition, the activeingredient compound is phenolic; in yet another embodiment, the compoundmay be a sterically hindered phenol. Other examples of preferredcompositions comprise effective antiviral amounts of a compoundaccording to the above formula; examples of appropriate compounds havebeen noted above.

In other embodiments, the compound is incorporated in a pharmaceuticallyacceptable carrier or excipient. In various alternative embodiments, thecomposition may be administered parenterally, orally, intraperitoneally,topically, transdermally, via inhalation, or liposomally.

In various alternative embodiments, methods for treating viral orretroviral infections in a living organism comprising administering to aliving organism an effective antiviral amount of any of the disclosedcompounds are suggested. The present invention also discloses methodsfor inhibiting viral or retroviral replication in a living organismcomprising administering an effective antiviral amount of any of thedisclosed compounds. In various embodiments of these methods, thecompound may be administered parenterally, orally, intraperitoneally,topically, transdermally, via inhalation, or liposomally. Further, themethods are useful for the treatment of plants or animals, includingmammals, and humans in particular.

The present embodiment additionally discloses a composition useful inthe treatment of viral and retroviral infections in living organisms,comprising an effective antiviral amount of an antioxidant compoundincorporated in a pharmaceutically acceptable carrier or excipient. Thepresent invention also discloses a method for inhibiting viral andretroviral replication and/or infections in living organisms comprisingadministering a composition comprising an effective antiviral amount ofan antioxidant compound incorporated in a pharmaceutically acceptablecarrier or excipient to a living organism.

Whether used to inhibit viral replication or to treat viral infections,other embodiments disclose that, for administration to plants, thecompounds are preferably dissolved or dispersed in a liquid medium(e.g., in an oil, or in an aqueous solvent with the aid of a detergentor other dispersant) at a concentration in the range of about 0.001% to1%, and applied by spraying or sprinkling. For administration toanimals, including mammals, the dosage units of the compositions wouldpreferably fall within the range of about 1 mg per kg of body weight, toabout 100 mg/kg, with a range of about 2 mg/kg to about 80 mg/kg beingeven more preferred.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 diagrams the chemical structure and labels used for some of thecompounds of the present invention.

FIG. 2 diagrams the chemical structure and labels used for some of thecompounds of the present invention.

FIG. 3 illustrates the results of tests measuring the effect of thecompounds of the present invention on syncytial cell formation.

FIG. 4 illustrates the results of tests measuring the effect of thecompounds of the present invention on p24 antigen levels.

DETAILED DESCRIPTION

We have observed that the membrane fluidity or other properties of viraland retroviral agents may be disturbed and affected by adminstration ofsubstituted compounds, or compositions or dosage unit forms, suchcompounds corresponding to the following formula: ##STR4## In thepresent specification and claims, n=1, 2, 3, or 4; m=0 or 1; Xrepresents O, S, CH₂, or R₃ ; R₁ represents hydrogen or tertiary butylor lower alkyl of from one to six carbon atoms, inclusive; R₂ representstertiary butyl or lower alkyl of from one to six carbon atoms,inclusive: and R₃ represents hydrogen or alkyl or aryl or mixedalkyl/aryl, containing a total of 5-25 carbon atoms.

A particularly preferred group of compounds for use in the practice ofthe invention comprises non-ionic compounds corresponding to the aboveformula. These compounds can be prepared as disclosed infra. For thesake of convenience, compounds having the above-described chemicalstructures will be referred to hereinafter as "BHT derivatives", or theymay also collectively be referred to herein as "antioxidants".

Other examples include S,S'-di-substituted mercaptals of an aldehyde oran S,S'-di-substituted mercaptole of a ketone containing from two totwenty carbon atoms, inclusive, wherein the substituents are3-tertiary-alkyl-4-hydroxy-5-lower alkyl phenyl groups in which thetertiary alkyl groups are tertiary butyl groups and the lower alkylgroups are methyl, ethyl, propyl or butyl.

One particular aspect of the invention comprises administration ofsterically hindered phenolic antioxidants, such compounds correspondingto derivatives of butylated hydroxytoluene (BHT), said derivativescomprising conjugates of from about one to four modified BHT moieties.Examples of such compounds include the following Ethanox® compounds,which are commercially available from Ethyl Corporation (Baton Rouge,La.):1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-benzene("Ethanox® 330"); octadecyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate("Ethanox® 376"); 4,4,'-§methylenebis(2,6-di-tert-butylphenol)("Ethanox® 702"); "Ethanox® 728", which is comprised of about 80 wt %methylene bridged polyalkyl phenols, over 50% of which comprises4,4'-methylenebis(2,6-di-tert-butylphenol), about 5 wt % solvents, andabout 15 wt % alkylated phenols, principally 2,4,6 tri-tert-butylphenol;1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-benzene("Ethanox® 330"); and octadecyl3,5-di-tert-butyl-4-hydroxyhydrocinnamate ("Ethanox® 376").

Examples of other effective antiviral antioxidants include:6-tert-butyl-2,4-dimethylphenol ("Ralox® 624"); tetrakis[methylene(3,5-di-tert-butyl-4-hydroxyhydrocinnamate)] methane ("Ralox®630"); 2,2'-methylene-bis(4-methyl-6-tert-butylphenol) ("Ralox® 2246");tert-butylhydroquinone ("Tenox® TBHQ"); and 2,6-dicyclohexyl-p-cresol(Ethyl Corporation, Baton Rouge, La.).

The above-referenced compounds can be administered topically, orally orparenterally by subcutaneous, intramuscular, intravenous orintraperitoneal injection or by implantation or the like, oraladministration being preferred. The antioxidant compounds, including BHTderivatives, are preferably administered as pharmaceutical compositionsin dosage unit form. Such compositions can be prepared by knowntechniques, for example, tableting or encapsulation. For administrationto humans, the dosage units of the antioxidants, including BHTderivatives, preferably contain from about 100, 200, or 500 milligrams(mg) to about one or five grams of the active ingredient. Dosage units,adapted for oral administration, such as liquids, tablets, capsules,lozenges, and the like, may contain up to about five grams of activeingredient, albeit they preferably contain from about 100 to about 500mg of the active ingredient, for ease of administration. The compoundscan also be administered as compositions adapted to be fed as part orall of the organism's diet.

For administration to plants, the compounds are preferably dissolved ordispersed in a liquid medium (e.g., in an oil, or in an aqueous solventwith the aid of a detergent or other dispersant) at a concentration inthe range of about 0.001% to 1%, and applied by spraying or sprinkling.For administration to animals, including mammals, the dosage units ofthe compositions would preferably fall within the range of about 1 mgper kg of body weight, to about 100 mg/kg, with a range of about 2 mg/kgto about 80 mg/kg being even more preferred.

In forming the compositions of the present invention, the activecompound is incorporated in a pharmaceutical carrier. In the presentspecification and claims, the term "pharmaceutical carrier" refers topharmaceutical excipients and includes nutritive compositions such assolid or liquid foodstuff. In the present specification and claims,"pharmaceutical excipient" refers to known pharmaceutical excipientswhich are substantially non-toxic and non-sensitizing at dosagesconsistent with their desired activity, e.g., with cholesterol reducingactivity, in the case of probucol. A preferred pharmaceutical carrieris, for example, a surface-active dispersing agent or a liposomalcarrier.

Suitable solid pharmaceutical carriers which can be employed forformulating the compositions of the invention include starch, lactose,glucose, sucrose, gelatin, microcrystalline cellulose, powderedlicorice, powdered tragacanth, malt, rice flour, silica gel, magnesiumstearate, magnesium carbonate, hydroxypropyl methyl cellulose, chalk andthe like, and compatible mixtures thereof. In the preparation of solidcompositions, the active ingredient can be triturated with a solidpharmaceutical carrier or mixtures thereof, or otherwise mechanicallymilled to obtain a uniform mixture. The mixtures can be compressed intotablets or filled into capsules by known procedures, or they can beemployed as powders or the like. The solid compositions generallycontain from about 0.02 to about 90 percent by weight, inclusive, of theactive ingredient, although neat dosages are also contemplated.

Among the liquid pharmaceutical carriers which can be utilized are ethylalcohol, propylene glycol, polyethylene glycols, peanut oil, corn oil,water, saline solution, liposomes, glycerides, glycerine and watermixtures, glucose syrup, syrup of acacia, mucilage of tragacanth and thelike, and compatible mixtures thereof.

The compounds of the present invention may be administered in variousefficacious amounts. The preferred dosage range of active ingredient foradult humans is from about 0.25 grams (gm) to about 5 gm per day, with arange of 0.5 gm to 2 gm per day being somewhat more preferable. Theactive ingredient may be administered topically, transdermally, orally,parenterally (e.g., subcutaneously, intravenously or intramuscularly),intraperitoneally, or via inhalation.

The membrane fluidity or other properties of viral and retroviral agentsmay also be disturbed via administration of a substituted compound, or acomposition or dosage unit form, being an S,S'-di-substituted mercaptalof an aldehyde or an S,S'-di-substituted mercaptole of a ketonecontaining from two to twenty carbon atoms, inclusive, wherein thesubstituents are 3-tertiary-alkyl-4-hydroxy-5-lower alkyl phenyl groupsin which the tertiary alkyl groups are tertiary butyl groups and thelower alkyl groups are methyl, ethyl, propyl or butyl. A particularlypreferred group of compounds for use in the practice of the inventioncomprises the bis(3-tert-butyl-4-hydroxy-5-lower alkylphenyl) ketonemercaptoles corresponding to the above formula. Another preferred groupcomprises the bis(3,5-di-tert-butyl-4-hydroxyphenyl) ketone mercaptolecompounds of the above formula, the compoundbis(3,5-di-tert-butyl-4-hydroxyphenyl) acetone mercaptole beingparticularly preferred for use in the composition and method of theinvention. These compounds can be prepared as disclosed in U.S. Pat. No.3,862,332.

For the sake of convenience, compounds having the above-describedchemical structures may be referred to hereinafter as "substitutedketone mercaptole" compounds. It is to be understood that thesecompounds may also function as antioxidants.

The above-referenced compounds can be administered topically, orally orparenterally by subcutaneous, intramuscular, intravenous orintraperitoneal injection or by implantation or the like, oraladministration being preferred. The antioxidant compounds, includingsubstituted ketone mercaptole compounds, are preferably administered aspharmaceutical compositions in dosage unit form. Such compositions canbe prepared by known techniques, for example, tableting orencapsulation. The dosage units of the antioxidants, including thesubstituted mercaptole compounds, preferably contain from about 100 toabout 200 to about 500 milligrams (mg) to about one to about five gramsof the active ingredient. Dosage units, adapted for oral administration,such as tablets, capsules, lozenges, and the like, may contain up toabout five grams of active ingredient, albeit they preferably containfrom about 100 to about 500 mg of the active ingredient, for ease ofadministration. The compounds can also be administered as compositionsadapted to be fed as part or all of the organism's diet.

In forming the compositions of the present invention, the activecompound is incorporated in a pharmaceutical carrier. In the presentspecification and claims, the term "pharmaceutical carrier" refers topharmaceutical excipients and includes nutritive compositions such assolid or liquid foodstuff. In the present specification and claims,"pharmaceutical excipient" refers to known pharmaceutical excipientswhich are substantially non-toxic and non-sensitizing at dosagesconsistent with their desired activity, e.g., with cholesterol reducingactivity, in the case of probucol. A preferred pharmaceutical carrieris, for example, a surface-active dispersing agent.

Suitable solid pharmaceutical carriers which can be employed forformulating the compositions of the invention include starch, lactose,glucose, sucrose, gelatin, microcrystalline cellulose, powderedlicorice, powdered tragacanth, malt, rice flour, silica gel, magnesiumstearate, magnesium carbonate, hydroxypropyl methyl cellulose, chalk andthe like, and compatible mixtures thereof. In the preparation of solidcompositions, the active ingredient can be triturated with a solidpharmaceutical carrier or mixtures thereof, or otherwise mechanicallymilled to obtain a uniform mixture. The mixtures can be compressed intotablets or filled into capsules by known procedures, or they can beemployed as powders or the like. The solid compositions generallycontain from about 0.02 to about 90 percent by weight, inclusive, of theactive ingredient, although neat dosages are also contemplated.

Among the liquid pharmaceutical carriers which can be utilized are ethylalcohol, propylene glycol, polyethylene glycols, peanut oil, corn oil,water, saline solution, liposomes, glycerides, glycerine and watermixtures, glucose syrup, syrup of acacia, mucilage of tragacanth and thelike, and compatible mixtures thereof.

The compounds of the present invention may be administered in variousefficacious amounts. The preferred dosage range of active ingredient isfrom about 0.25 grams (gm) to about 5 gm per day, with a range of 0.5 gmto 2 gm per day being somewhat more preferable. The active ingredientmay be administered topically, transdermally, orally, parenterally(e.g., subcutaneously, intravenously or intramuscularly),intraperitoneally, or via inhalation.

The invention can be better understood by way of the following exampleswhich are representative of the preferred embodiments thereof, but whichare not to be construed as limiting the scope of the invention.

EXAMPLE I Synthesis of Analogs

The purity of each compound was confirmed by melting points and by thinlayer chromatography. The structure of each compound was confirmed bynuclear magnetic resonance (NMR) spectroscopy. The compounds referred tobelow are illustrated in FIGS. 1 and 2.

I, II, III:

These compounds were prepared by standard methods of synthesis ofthioethers, via displacement of halide ion from an alkyl halide with athiophenolate nucleophile. (See, for example, March, J., AdvancedOrganic Chemistry, 3d ed., J. Wiley and Sons, 1985, pp. 360-362.) Thus2,6-di-tert-butyl-4-mercaptophenol was reacted with 1,12-dibromododecane(for I), p-xylylene dibromide (for II), or 1,4-dibromobutane (for III),in N,N-dimethylformamide in the presence of powdered potassiumcarbonate. The products were washed free of solvents and salts withwater and purified by recrystallization from organic solvents.

Compound I had the appearance of white crystals from isopropyl alcohol,with a melting point between 74-75° C. Compound II appeared as whitecrystals from isopropyl alcohol, with a melting point between 159-161°C. Compound III appeared as white crystals from isopropyl alcohol, witha melting point between 143-145° C.

IV, VI, IX, X;

These ketone mercaptoles were prepared by standard methods of synthesisin which a thiophenol is condensed with a ketone under acid catalysis inan organic solvent (see, e.g., March, J., Advanced Organic Chemistry, 3ded., J. Wiley & Sons, 1985, pp. 793-795). Thus,2,6-di-t-butyl-4-mercaptophenol was reacted with acetone (for IV),dimethyl gamma-ketopimelate (for VI), N-methyl-4-piperidone (for IX), ormethyl pyruvate (for X, methyl ester) and the products were purified byrecrystallization from organic solvents.

Compound IV appeared as white crystals from ethanol, melting point125-126° C. Compound VI appeared as white crystals from isopropylalcohol, melting point 152-154° C. Compound IX appeared as whitecrystals from isopropyl alcohol, melting point 254-256° C. Compound X,methyl ester, appeared as white crystals from isopropyl alcohol with amelting point of 111-113° C.

With respect to Compound X, the free acid was prepared from the methylester by saponification with sodium hydroxide, followed by acidificationwith HCl. White crystals were obtained and purified by crystallizationfrom hexane, said crystals having a melting point of 151-153° C.

Compound V was synthesized by the method of T. Fujisawa, et al.,Synthesis 39 (1973). Yellow crystals were obtained after crystallizationfrom benzene/toluene, and had a melting point of about 137-138° C.

Additional analogs labeled XI-XIX (and further identified with "testcode" nos., e.g., 1293-27-5), such as those diagrammed in FIG. 2, wereprepared as described above, except for those obtained from variousidentified sources. As noted earlier, the Ethanox® compounds may beobtained from Ethyl Corporation, Baton Rouge, La.; Ralox® is obtainablefrom Raschig AG, Ludwigshafen, Germany; and Tenox® may be obtained fromEastman Chemical Products, Kingsport, Tenn.)

Analogs XI-XIX may be further identified as follows:

XI: 3,5-di-t-butyl-4-hydroxyphenyl β-D-thioglucopyranoside;

XII: bis(3,5-di-t-butyl-4-methoxyphenyl) mercaptole;

XIII: octadecyl 3,5-di-t-butyl-4-hydroxyhydrocinnamate (Ethanox® 330);

XIV: 2,6-di-t-butyl-4-(dodecylthio)phenol;

XV: 2,6-di-t-butyl-4-(octadecylthio)phenol;

XVI: 1,10-di(3,5-di-t-butyl-4-hydroxyphenylthio)decane;

XVII: 1,14-di(3,5-di-t-butyl-4-hydroxyphenylthio) tetradecane;

XVIII: 2-octanone bis(3,5-di-t-butyl-4-hydroxyphenyl) mercaptole;

XIX: acetoacetic acid bis(3,5-di-t-butyl-4-hydroxyphenyl) mercaptole.

EXAMPLE II In Vitro Inhibition Tests

The following compounds were tested for their ability to inhibit HIV-1virus infection in vitro. The compounds tested were: 1)1,12-di(3,5-di-tert-butyl-4-hydroxyphenylthio)dodecane; 2)α,α'-di(3,5-di-tert-butyl-4-hydroxyphenylthio)-p-xylene; 3)1,4-di(3,5-di-tert-butyl-4-hydroxyphenlythio)butane; 4) acetonebis(3,5-di-tert-butyl-4-hydroxyphenyl) mercaptole ("probucol"); 5) bis(3,5-di-tert-butyl-4-hydroxyphenyl) sulfide: 6) dimethylgamma-ketopimelate bis(3,5-di-tert-butyl-4-hydroxyphenyl) mercaptole; 7)bis(3,5-di-tert-butyl-4-hydroxyphenyl) methane; 8)2,6-di-tert-butyl-4-methylphenol) (BHT); 9) N-methyl-4-piperidonebis(3,5-di-tert-butyl-4-hydroxyphenyl) mercaptole; and 10) pyruvic acidbis (3,5-di-tert-butyl-4-hydroxyphenyl) mercaptole.

Preparation of Test Solutions

The stock solutions of the compounds consisted of DMSO (dimethylsulfoxide) containing from 1% to 3% w/v of the compound. These stocksolutions were diluted into the aqueous test media as needed to achievethe desired final concentration. An additional control in each test setcontained DMSO only. The concentrations tested were as follows:

1) 300 μg/ml (1%-3% DMSO);

2) 100 μg/ml (1% DMSO);

3) 30 μg/ml (dilute in medium containing 1% DMSO);

4) 10 μq/ml (dilute in medium containing 1% DMSO);

5) 3 μg/ml (dilute in medium containing 1% DMSO);

6) 1 μg/ml (dilute in medium containing 1% DMSO).

The controls included: 1) 3% DMSO, uninfected; 2) 1% DMSO, uninfected;3) no DMSO, uninfected; 4) AZT 10 μM, 1% DMSO; 5) AZT 1 μM, 1% DMSO; 6)No drug, infected, 3% DMSO; and 7) no drug, infected, 1% DMSO.

Testing Protocol

Prepare 15 ml of each of the media at the indicated concentrations ofcompound and/or solvent. A washed pellet consisting of 1.5×10⁶ cells ofMolt-3 (a clonal derivative of a lymphocyte (T-cell) line of Japaneseorigin, obtained from the National Institutes of Health, Bethesda, Md.)was suspended in 1 ml of each compound or control medium. Each tube wasincubated with occasional shaking at 37° for four hours.

During the last hour of the preincubation period, Molt-3 grown HIV-1 wasdiluted into 1 ml each of the media to provide 200 TCID₅₀ units.Polybrene (10 μg/ml) was included in each tube.

The cells were pelleted and resuspended in the virus-containing media,then incubated for 60 minutes at 37° with occasional shaking. The cellswere then pelleted and resuspended in 5 ml of each medium. Each cellpellet was washed twice in complete growth medium, then transferred tolabeled 6-well trays.

On a daily basis, giant cells and syncytia were counted. At the sametime, 0.5 ml of the culture was removed and frozen at -70° C. Freshmedium was used for replenishment.

At the end of three days, antigen capture analysis by immunoassay wasperformed. At the end of a 4-5 day period, uninfected cells were testedfor viability by Trypan Blue exclusion.

Results

    ______________________________________                                        Screening of Drugs in the Molt-3/HIV 1 Assay System                                     50% reduction in                                                      Cmpd syncytium 50% reduction in 50% kill of                                   (Drug) formation p24 antigen host cells                                     ______________________________________                                        I     <1     μg/mL <1    μg/mL                                                                             300    μg/mL                              II <1  <1  300                                                                III 3  3  150                                                                 IV 3  5  150                                                                  V 1  <1  50                                                                   VI <1  2  50                                                                  VII 3  2  50                                                                  VIII <1  2  15                                                                IX <1  <1  10                                                                 X 2  <1  5                                                                  ______________________________________                                    

Column 1 lists the identification number of each substance. Themolecular structure of each substance appears in FIG. 1. Column 2 liststhe approximate concentration of each compound that produces a 50%reduction of syncytial cells, relative to syncytial cell formation in aninfected control that lacks the compound. The reported concentration isan average of the results obtained after 2, 3 and 4 days of incubation.Syncytial cell formation is an indicator of the cytopathic effect ofHIV-1 infection in the host cell, and the results show that all of thecompounds are effective at concentrations of 3 μg/mL or less.

Column 3 lists the approximate concentration of compound that produces a50% reduction of soluble p24 antigen, as measured by a p24 captureimmunoassay. The reported concentration is the result of measurementstaken after 3 days of incubation, relative to infected controls lackingthe compound. The p24 is a characteristic protein component of the HIVcore, and its concentration is indicative of HIV concentration. Theresults show that all of the compounds are effective at concentrationsof 5 μg/ml or less.

Column 4 lists the approximate concentration of compound that produces a50% reduction in the viable population in uninfected host cells,compared to the population of surviving host cells in an uninfectedcontrol, measured after 5 days of incubation. The results show majordifferences in compound toxicity, ranging from low toxicity (I, II) tohigh toxicity (IX, X).

Discussion

The data show that all of these compounds are very active in reducingsyncytial cell formation and p24 antigen levels. More significantly, aclear and obvious structure/activity correlation emerges with respect totoxicity of the compounds. The most highly toxic structures are IX and Xwhich, under physiological conditions, are ionic and highly polar, ie.,negatively charged carboxylate anion (X) and positively charged ammoniumion (IX).

Compounds I through VIII are non-ionic and constitute a series withgenerally decreasing polarity (increasing lipophilicity). The phenolic--OH group, common to all the structures, is weakly polar. Carboxylateester groups (as in VI) are less polar, and the remaining structuralcomponents (alkyl, aryl, thioether) are least polar or non-polar.Compounds I through V comprise the clearest examples of progressiveincrements of alkyl and/or aryl groups (increasing lipophilicity) andthe attendant decreases in toxicity.

Compound VIII is BHT, which has significant antiviral properties.Compound IV is probucol, whose antiviral properties are also illustratedherein. The present study establishes for the first time a correlationbetween structure and activity in this new class of antiviral agents,and a rational basis for the design of related compounds with improved"therapeutic window", ie., higher ratios of effectiveness to toxicity.Thus, on the basis of the assay system shown in the table above, analogsI and II have therapeutic windows that are at least ten times betterthan that of probucol (IV) and at least thirty times better than that ofBHT (VIII).

Additional data are provided in FIGS. 3 and 4. While there is a largeexperimental variability in the results, all the analogs demonstratesubstantial activity, albeit some consistently outperform the others.

An improved therapeutic window for an antiviral agent is of paramountimportance for the successful treatment of viral infections, sinceefficacy can then be improved without increasing toxicity and otheradverse side effects. It is further believed that these greatly improvedantiviral analogs of BHT also exhibit improved utility in some of thetherapeutic applications discussed herein, e.g., in the treatment ofAIDS, CMV, Herpes, and SFV infections.

EXAMPLE III Clinical Tests

Probucol was administered to 6 adult male documented HIV-positive (HIV+)patients, ranging in age from 31-44 years at the time of diagnosis, indosages consistent with those prescribed for treatment ofhypercholesterolemia. All patients receiving probucol took 1 gram perday (with the exception of Patient F, who received 4.5 g/day) in divideddoses for individually-varying lengths of time, as indicated below. Eachpatient was examined regularly and clinical observations were made andrecorded by the same treating physician each time, except whereindicated otherwise. Samples of each patient's blood were collectedperiodically and were tested for levels of T helper cells (CD4⁺ or T4)and T suppressor cells (CD8⁺ or T8). The CD4⁺ :CD8⁺ ratio ("R") was alsocalculated each time. Blood samples taken prior to the initiation ofprobucol treatment were analyzed and compared with the samples takenduring the treatment phase. The same parameters were tested in allsamples. The results of this testing are set out below:

    ______________________________________                                        Patient                                                                             Date      Clin. Observations                                                                              Test Results                                ______________________________________                                        A     5/6/88    HIV+ (determined  T4 - 532                                        2/26/88); asympto- T8 - 1427                                                  matic. R - 0.37                                                              5/7/88 1 g/day probucol begun,                                                 in divided doses.                                                            11/16/88 Asymptomatic. T4 - 1111                                                T8 - 1910                                                                     R - 0.58                                                                    5/5/89 Asymptomatic. T4 - 1161                                                  T8 - 1879                                                                     R - 0.62                                                                   B 12/30/37 AIDS with Kaposi's T4 - 146                                          sarcoma. Received T8 - 393                                                    treatment with AZT R - 0.37                                                   prior to this time.                                                           AZT treatment was                                                             discontinued when                                                             patient became ill                                                            and developed a                                                               significant anemia.                                                          12/31/87 1 g/day probucol begun,                                               in divided doses.                                                            4/8/88 Kaposi's lesions T4 - 263                                               smaller. T8 - 867                                                              R - 0.30                                                                    12/1/88 Lesions smaller T4 - 344                                               and fewer in T8 - 847                                                         number. R - 0.41                                                             3/10/89 Smaller lesions, T4 - 347                                              and fewer in T8 - 583                                                         number. R - 0.60                                                            C 12/9/87 ARC (AIDS-related T4 - 601                                            complex): thrush, T8 - 978                                                    eczema and R - 0.61                                                           lymphadenopathy                                                              6/6/88 Same as above T4 - 533                                                   T8 - 866                                                                      R - 0.62                                                                    6/7/88 1 g/day probucol begun,                                                 in divided doses.                                                            8/12/88 Clinical symptoms T4 - 654                                             improved. T8 - 515                                                             R - 1.27                                                                   D 4/14/87 Fatigue and rash* T4 - 530                                             T8 - 2000                                                                     R - 0.30                                                                    6/30/87 HIV+ (first                                                            documented)*                                                                 7/1/87 Increasing fatigue, T4 - 380                                            rash and lymph T8 - 1260                                                      node swelling* R - 0.30                                                      10/28/87 ARC: symptoms of T4 - 247                                             thrush, eczema, T8 - 845                                                      and generalized R - 0.30                                                      lymphadenopathy.*                                                            11/5/87 1 g/day probucol begun,                                                in divided doses.                                                            12/1/87 Symptoms improved. T4 - 457                                             T8 - 1828                                                                     R - 0.25                                                                    2/2/88 Symptoms resolved. T4 - 520                                              T8 - 1751                                                                     R - 0.30                                                                    6/7/88 Symptom-free. T4 - 512                                                   T8 - 1536                                                                     R - 0.33                                                                   E 3/19/87 HIV+; T4 - 710*                                                       Asymptomatic.* T8 - 1450*                                                      R - 0.50*                                                                   7/14/87 Asymptomatic.* T4 - 560*                                                T8 - 1230*                                                                    R - 0.50*                                                                   2/3/88 Asymptomatic.* T4- 520*                                                  T8 - 1102*                                                                    R - 0.47*                                                                   4/27/88 1 g/day probucol begun,                                                in divided doses.                                                            8/17/88 Asymptomatic. T4 - 679                                                  T8 - 1462                                                                     R - 0.46                                                                   F 8/88 Diagnosed with T4 - 116                                                  AIDS, Kaposi's T8 - 1468                                                      sarcoma.* R - 0.08                                                           9/88 Treatment with                                                            AZT begun.*                                                                  7/89 Showing increased                                                         fatigue, HIV viremia,                                                         Kaposi's sarcoma                                                              fever (to 104-106)                                                            Weight loss: 20 lbs                                                           in one month.                                                                8/10/89  T4 - 111                                                             8/16/89 AZT treatment stopped                                                  due to increasing                                                             HIV viremia.                                                                 8/24/89 Viral culture T4 - 37                                                  shows high concen-                                                            tration of HIV in                                                             the serum.**                                                                 9/01/89 Daily treatment begun                                                  with 1282-4-1, at 3 g/day.                                                   9/06/89 Dosage increased to                                                    4.5 g/day.                                                                   9/14/89  T4 - 45                                                              9/21/89 Afebrile; Kaposi's                                                     lesions shrinking.                                                            Weight gain of 15                                                             lbs. over last 2 weeks.                                                       Viral culture of serum                                                        shows no detectable HIV.**                                                   11/7/89  T4 - 85                                                           ______________________________________                                         *Information reported by prior treating physician.                            **Culture method: obtain sample of peripheral blood, coculture with           phytohemagglutinin (PHA), measure increase of p24 vs. time. (See Lane, et     al., "Acquired Immunodeficiency Syndrome and Related Diseases", in Rose,      et al., eds.,  Manual of Clinical Laboratory Immunology, 3d Ed., Am. Soc.     Microbiol., pp. 582-586, 1986.)                                          

EXAMPLE IV In Vitro Inhibition Tests

The following compounds were tested for their ability to inhibit HIV-1virus infection in vitro. The compounds tested were: 1) probucol (2.5%);2) 2,6 dicyclopentyl phenol (5%); 2,6 dicyclohexyl p-cresol (5%); 3)4,4'-thiobis(6-tert-butyl-o-cresol) ("Ethanox® 322", 5%); 4)4,4'-methylenebis(2,6-di-tert-butylphenol) ("Ethanox® 702", 1.25%); 5)2,6-di-tert-butyl-α-dimethylamino-p-cresol ("Ethanox® 703", 5%); 6)1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl) benzene("Ethanox® 330", 1.25%); and 7)4,4'-methylenebis(2,6-di-tert-butylphenol) ("Ethanox® 728", 5%).

The compounds were diluted at 300, 200, 100, 30, 10, 3, and 1 microgramper milliliter (1 μg/ml) in Complete RPMI 1640 media (GibcoLaboratories, Grand Island, N.Y.). The compound dilutions werepre-incubated with an HIV-1 (10 3.6 titer) diluted at 1:100 and 1:1000for one hour and then plated onto a CEM-SS infectivity assay. (See Nara,et al., Aids Res. and Human Retroviruses 3: 283-302 (1987), Mary AnnLiebert, publ., or Nara and Fischinger, Nature 332: 469-470 (1988)). Thedilutions were also pre-incubated onto the cells for one hour, theninoculated with 1:100 and 1:1000 dilutions of the HIV-1(10 3.6 titer)that contained no compound. Inoculum was aspirated off the wells afterone hour and the cells were maintained for five days with compound andmedia, then read for plaques.

Of the above-listed compounds, probucol displayed the most significanteffects upon HIV-1 plaque formation. It was specifically observed thatprobucol significantly inhibited plaque formation at concentrations ofabout 200 μg/ml under both test conditions--i.e., when pre-incubatedwith the HIV and when pre-incubated with the cells, without significanttoxicity to the cells. Probucol also appeared to inhibit plaqueformation at concentrations of about 100 μg/ml, albeit the inhibitionwas not as marked as at twice the concentration. Again, there was nosignificant toxicity to the cells. The effects of the Ethanox® compoundstested were, in most cases, not always as marked as were those ofprobucol. Nevertheless, these phenolic antioxidants, and in particular,Ethanox® 728, demonstrated efficacy as antiviral and antiretroviralagents.

EXAMPLE V Effect of Drugs Against CMV in HS68 Cells Virus Dilution (LogFactor) at Which a Cytopathic Effect is Seen.

    ______________________________________                                                Concentration of Drug, μg/ml                                       Drug      300    100      30    10    3    1                                  ______________________________________                                        TEST SET A                                                                      1293-27-2  T* T T 4 5 6                                                       1293-27-3 T T T >7 >7 7                                                       1293-24-4 T   7 7 7 6 7                                                       1293-27-5 T   4 6 7 7 6                                                       Acyclovir -- <2 -- 7.0 --  7.0                                                TEST SET B                                                                    1297-12-3 >6.5   >6.5   6.5 >6.5 6.5 6                                        1297-12-7 >6.5   >6.5  >6.5 >6.5 >6.5 >6.5                                    1297-12-8 T T T 6.5 >6.5 >6.5                                                 1297-12-11 T T T T 6 6.5                                                      1297-12-12 T T T <4 6.5 >6.5                                                  Acyclovir -- <4 -- 4.5 --  6.5                                              ______________________________________                                         (*T denotes a toxic effect.)                                                  [Test Set A is part of Test Set 3 (see FIGS. 3 and 4). Cytopathic effects     were scored on day 9.                                                         [Test Set B is part of Test Set 4 (see FIGS. 3 and 4). Cytopathic effects     were scored on day twelve.                                               

HS68 cells were preincubated with CMV for one hour at 37° C. at theindicated virsus dilution, and then exposed to drugs at concentrationsranging from 300 μg/ml to 1 μg/ml. The drugs were dispensed from 3%stock solutions in DMSO, and the final concentration of DMSO in eachtest well was ajusted to 1%. The wells were scored for cytopathiceffects on the indicated days.

EXAMPLE VI Effect of Drugs Against HSV-1 in HS68 Cells Virus Dilution(Log Factor) at Which a Cytopathic Effect is Seen.

    ______________________________________                                                Concentration of Drug, g/ml                                           Drug      300    100     30    10    3     1                                  ______________________________________                                        TEST SET A                                                                      1293-27-2 6 7 7 8 7    7                                                      1293-27-3 T T T 7 7   7                                                       1293-27-4 8 8 7 7 7   7                                                       1293-27-5 T 7 7 7 7   7                                                       Acyclovir -- <4   -- <4 -- 5                                                  TEST SET B                                                                    1297-12-3   7.5   7.5   7.5 7.5 7.5 7.5                                       1297-12-7   7.5 7 7 7.5 7.5 7                                                 1297-12-8 T T   7.5 7.5 7.5 7.5                                               1297-12-11 T T T T 7.5 >7.5                                                   1297-12-12 T T 7 7.5 7.5 7                                                    Acyclovir -- 5 -- 5 -- 5                                                    ______________________________________                                         [Test Set A is part of Test Set 3 (see FIGS. 3 and 4). Cytopathic effects     were scored on day three.                                                     [Test Set B is part of Test Set 4 (see FIGS. 3 and 4). Cytopathic effects     were scored on day three.                                                

HS68 cells were preincubated with HSV-1 for one hour at 37° C. at theindicated virus dilution, and then exposed to drugs at concentrationsranging from 300 g/ml to 1 g/ml. The drugs were dispensed from 3% stocksolutions in DMSO, and the final concentration of DMSO in each test wellwas adjusted to 1%. The wells were scored for cytopathic effects on theindicated days.

Although the invention has been described in the context of particularembodiments, it is intended that the scope of coverage of the patent notbe limited to those particular embodiments, but be determined byreference to the following claims.

What is claimed is:
 1. A method for inhibiting infectivity of a viruscomprising contacting the virus with an effective amount of a compoundhaving the formula: ##STR5## wherein m=1; n=2; X is sulfur; R₁ ishydrogen or a lower alkyl from 1-6 carbon atoms; R₂ is a lower alkylfrom 1-6 carbon atoms; and R₃ is an alkyl, an aryl or a mixedalkyl/aryl, containing from 1-25 carbon atoms.
 2. The method of claim 1wherein the virus is HIV.
 3. The method of claim 1 wherein the virus iscytomegalovirus.
 4. The method of claim 1 wherein the virus is HerpesSimplex virus.
 5. The method of claim 1 wherein said administering is exvivo.
 6. A method of inhibiting infectivity of a virus in a compositioncomprising blood, a blood component, cell culture or a component of cellculture comprising administering an effective antiviral amount of acompound having the formula: ##STR6## wherein m=1; n=2; X is sulfur; R₁is hydrogen or a lower alkyl from 1-6 carbon atoms; R₂ is a lower alkylfrom 1-6 carbon atoms; and R₃ is an alkyl, an aryl or a mixedalkyl/aryl, containing from 1-25 carbon atoms.
 7. The method of claim 6wherein the virus is HIV.
 8. The method of claim 6 wherein the virus iscytomegalovirus.
 9. The method of claim 6 wherein the virus is HerpesSimplex virus.